Sound is one of the major components of our everyday life. We experience it every day, and it has become a vital part of our daily agenda. Humans are capable of distinguishing more than 300,000 different tones. Some of these tones could be the bothersome buzzing of a mosquito, the sound emitted when someone taps their fingers on a desk, or the roaring sound of a glorious trumpet.
Check out this presentation featuring a multimedia project made by Sean Erwin and Zac Montgomery!
Procreation
When a guitar string is plucked, a common observation made is how the string vibrates depending on the size of the string. Sound is produced whenever an object vibrates. Vibrations are the result of a disturbance occurring between multiple objects. In other words, sound is produced whenever an object is violated of its equilibrium, and it resonates a sound as it attempts to conform back to its original position. Some accounts of this process can be observed through the sound produced by striking a tuning fork or crashing together a pair of cymbals. These disturbances have the ability to travel through all forms of matter. It travels at different velocities depending on the form of matter it flows through, which is called the medium. A disturbance flows through solids the quickest, followed by liquids and gases in that order. The transportation of these vibrations has an effect on the tonality of the resulting sound as well.[1]
Waves
Sine Wave, courtesy of http://www.doctronics.co.uk/signals.htm
There are two different basic types of mechanical waves that are classified based on the type of vibrations. One such wave is referred to as a transverse wave. A transverse wave is what occurs when a medium vibrates at a ninety-degree angle relative to the direction that energy moves. They are usually visualized as sinusoidal and have several components. They are made up of crests (the topmost point) and troughs (the lowest point), which are found relative to its rest position. The distance from the center to these points is called the amplitude (A). The amplitude is often referred to as the loudness the vibration gives off, which is measured in a unit called a decibel (dB). If one wanted to find the wavelength (λ), they would measure the distance from one adjacent crest/trough to the other. Two units are commonly associated with the wavelength: the frequency and the period. The frequency(f) is the amount of vibrations per second, which is measured in Hertz (Hz; Ex. 440 Hz = 440 vibrations per second). The period(T) is the amount of time it requires a wavelength to pass a select point.
The other type of wave is called a longitudinal (compressional) wave, in which the medium vibrates parallel to the direction of travel. A visual representation of a longitudinal wave would be the vibrations produced when you apply a force to a slinky. Sound is a longitudinal wave that travels through the air as compressional waves, where a pulse travels in all directions. This pulse is split up into two different pressurized wave motions. One of these areas of motion is the compression, where the air molecules are most concentrated or 'compressed'. The disturbance that is left behind these compressions are rarefactions, the less concentrated part of the compressional wave. GoAnimate.com: Sound IS AWESOME by sterwin17
Interference is referred to as the collision and merging of two waves. When two waves combine, the sum of the amplitudes at different points of each wavelength produces the resulting wave. These results are known as constructive and destructive interference. Many factors are considered in the result of a particular interference. For example: Amplitude, Wavelengths, Timbre, Etc.
Interference, courtesy of http://paws.kettering.edu/~drussell/Demos/superposition/superposition.html
Constructive Interference
Constructive interference occurs when the amplitude of both waves at a particular point are either above the node. The same holds true for amplitudes below the node. Because they are both in the same direction, the "quantities" would be added and still in the same direction. This happens most consistently when two waves of the exact same frequency are played together.
Constructive Iterference, courtesy of http://obergscience.com/page3.htm
Destructive Interference
Destructive interference occurs when the amplitude of one of the two waves at a particular point is above the node while the other is below the node. Because they are in opposite directions of the node, the "quantities" cancel each other out. This occurs most consistently when two waves of the exact same frequency are played together but completely out of phase.
Destructive Iterference, courtesy of http://obergscience.com/page3.htm
Harmonics
Whenever a note is played on any instrument, it sends out multiple simultaneous frequencies. The original desired note that was played by the instrument is called the fundamental frequency, and the other tones that formed as a result of it are called modes. The frequencies of the higher modes are called overtones, which are apparent in all instruments; however, it differs between percussive and wind instruments. Wind instruments produce overtones called harmonics, which are named so because the overtones are "harmonically" related to the fundamental frequency that was produced by the instrument. Harmonics are simply multiples of the fundamental frequency that occur simultaneously (100 Hz, 200 Hz, 300 Hz, etc.). If each overtone is related to one another harmonically, then each one, including the fundamental frequency, can be classified as a harmonic. The fundamental frequency is essentially the first harmonic, and then first overtone becomes the second harmonic, which means the second overtone is the third harmonic, etc. Every instrument has its own unique spectrum of sound that outputs different harmonics whenever a tone is played; hence the explanation for timbre.
Hornbostel-Sachs System
Instruments are normally classified by their cultural background, how they produce sound (as well as the sound they produce), acoustics, and many other characteristics. This method of organization is appropriately called organology. A common method of classifying an instrument is the type of element that is associated with it, which can be traced back to Roman and Greek times. The five types elements that instruments are classified under are as follows: solids (gaiaphones), liquids (hydraulophones), gases (aerophones), plasma (plasmaphones), and quintessential (electrophones).[2] One well known classification system is the Hornbostel-Sachs system. It was put together by ethnomusicologist Erich Moritz von Hornbostel and musicologist Curt Sachs. The model is based off of the Dewey Decimal classification system and categorizes instruments based on their shape, air columns, the strings, and the membrane.[3]
I: Idiophones
This level includes any instrument that emits sound directly from its body after being struck without the assistance of an air column, membrane or string. They are classified into different sub-genres based on the method that they are stricken. Idiophones are also known as "gaiaphones" because they are solid instruments that maintain their shape.
Examples of idiophones include:
Cymbals
Castanets
Xylonphones
Chimes
II: Membranophones
This level includes any instrument that produces sound from the vibration of its membrane. Nearly all drums can be placed into this category because their heads vibrate whenever struck by an object. These instruments can also be classified as gaiaphones.
Examples of membranophones include:
Snare drum
Timpani
Bass drum
Kettle drum
Kazoo
III: Chordophones
Instruments classified in this system create sound from the vibration of its string(s). The pitch of the instrument is primarily based on the tension in the string or primarily rely on a resonator box etc. Like idiophones and membranophones, these would also be gaiaphones.
Examples of chordophones include:
Guitar
Violin
Double bass
Banjo
IV: Aerophones
This level includes the instruments where the production of sound is simply made from air. There are many sub levels in this category because there are many kinds of wind instruments with different structures and embouchures required to play them. Some do not require keeping air inside of the instrument itself to produce sound while most require a body in which to resonate. This level maintains the name of the element from which it originates.
Examples of aerophones include:
Whip
Saxophone
Harmonica
Trombone
Ocarina
V: Electrophones
The fifth category includes instruments that create sound from electrical means. This category is more broadly known as the quintessential element because it also involves processes not limited by matter.
Examples of electrophones include:
Theremin
Turntables
Optical computing
Neurological networking
Experiment
We conducted an experiment to determine how the change in timbre of a wave would affect the resultant tones of the two played notes. The experiment consisted of recording multiple tones on four different instruments. The procedure, results, etc. have been outlined below.
Materials
TrueRTA(Real Time Analyzer) Software
Reliable USB Microphone
Trumpet
French Horn
Clarinet
Tenor Saxophone
Printer
Procedure
Planned Procedure
1. Start up the TrueRTA Software and bring up the Oscilloscope Mode. This will take the imported sound files and convert them to a graph in real time.
2. Plug in the microphone and change the software input to that microphone. 3. Use the software's generator function in order to produce a sine wave for a concert Bb and D to use as a reference.[4] Save each to the software memory and print. 4. Record each of these notes on all four instuments demonstrating the shape of each intstruments timbres. Save each to the software memory and print. 5. Have the Trumpet player play a third space C in the Treble Clef and the Clarinet player play a fourth space E in the Treble Clef at a comfortable Forte while recording. The resultant tone should be a fourth space G in the Bass Clef in accordance to the frequencies. Save the graphs to memory and print. 6. Change to the software's frequency analyzer. Repeat the same pitches. This should should show evidence of lower frequency waves due to the resultant tone. Save and Print these bar graphs. 7. Repeat steps 5 and 6 with the following pitches: Trumpet-C and Tenor Sax-E, French Horn-F and Clarinet-E, and French Horn-F and Tenor Sax-E. All resultant tones should be a low G in accordance to the frequencies.
Actual Procedure Differences
1. We recorded all individual pitches with the use of a metronome, as opposed to using the generator function to produce "control" graphs, with only the frequency analyzer and saved each to memory.
2. We repeated this process for the combinations of all instruments, again with only the frequency analyzer, and saved each to memory.
Problems
1. We found it much to difficult to get an accurate enough graph of each example of timbre through the oscilloscope mode.
2. We were unable to figure out how to change the setting on the frequency analyzer to give us a more accurate reading, but the data obtained show sufficient results.
Data
Frequency Ranges (Hz)
Trumpet Volume (dB)
Tenor Sax Volume (dB)
French Horn Volume (dB)
Clarinet Volume (dB)
Clarinet/Trumpet Volume (dB)
Clarinet/ Horn Volume (dB)
Sax/ Trumpet Volume (dB)
Sax/ Horn Volume (dB)
10 – 20
-44
-40
-41.2
DNR
-41.5
-40.5
-35.2
-34
20 – 50
-48
-41
-39.5
DNR
-45
-42
-29
-23.6
50 – 100
-37.5
-36.2
-40.5
-44.2
-33.5
-37.6
-23
-18
100 – 200
-36.2
-29.2
-46
-27.5
-11
-19.8
-10.8
-9.5
200 – 500
-30.8
-0.5
-39.5
-26.2
-13.2
-8.6
7.6
0.8
500
1.5
-6.4
8.6
5
4
6.5
-3
4.2
1k
-4.5
2.5
0.2
-21.2
1
-5
0.2
-3
2k
-9.5
1
-4.5
-6.2
-4.5
-5.6
-4
-6.2
2k – 5k
-15.5
-6.6
-7.5
-9
-7.5
-10
-8.2
-10.4
5k – 10k
-24
-12.5
-16
-17
-15
-17.2
-15.4
-17.2
10k – 20k
-40
-27
-31.5
-30
-28.5
-31
-30
-31.1
Results and Conclusions
As it turns out, the saxophone is a very interesting instrument. For this experiment, we used a tenor saxophone which, to the ear, actually sounds an octave and one whole step lower than its written note. When we recoded and graphed the frequency levels, we saw that it had picked up the low frequencies the strongest as expected. However, we noticed an odd data sample. It actually produced a high frequency sound wave as well! At first, I figured that it was due to some sort of outside interference. We recorded the tenor saxophone three separate times, and all three times we got similar results. When we recorded the Clarinet, Trumpet and French Horn, there was no evidence of these high pitch frequencies outside of the expected frequencies. For each combination of these instruments, we saw great increases in the 100-200Hz region. The most significant of these increases was in the Clarinet/Trumpet combination which was to be expected as these two are our main instrument and likely to show the optimal results.
Table of Contents
Sound
Sound is one of the major components of our everyday life. We experience it every day, and it has become a vital part of our daily agenda. Humans are capable of distinguishing more than 300,000 different tones. Some of these tones could be the bothersome buzzing of a mosquito, the sound emitted when someone taps their fingers on a desk, or the roaring sound of a glorious trumpet.
Check out this presentation featuring a multimedia project made by Sean Erwin and Zac Montgomery!
Procreation
When a guitar string is plucked, a common observation made is how the string vibrates depending on the size of the string. Sound is produced whenever an object vibrates. Vibrations are the result of a disturbance occurring between multiple objects. In other words, sound is produced whenever an object is violated of its equilibrium, and it resonates a sound as it attempts to conform back to its original position. Some accounts of this process can be observed through the sound produced by striking a tuning fork or crashing together a pair of cymbals. These disturbances have the ability to travel through all forms of matter. It travels at different velocities depending on the form of matter it flows through, which is called the medium. A disturbance flows through solids the quickest, followed by liquids and gases in that order. The transportation of these vibrations has an effect on the tonality of the resulting sound as well.[1]
Waves
The other type of wave is called a longitudinal (compressional) wave, in which the medium vibrates parallel to the direction of travel. A visual representation of a longitudinal wave would be the vibrations produced when you apply a force to a slinky.
Sound is a longitudinal wave that travels through the air as compressional waves, where a pulse travels in all directions. This pulse is split up into two different pressurized wave motions. One of these areas of motion is the compression, where the air molecules are most concentrated or 'compressed'. The disturbance that is left behind these compressions are rarefactions, the less concentrated part of the compressional wave.
GoAnimate.com: Sound IS AWESOME by sterwin17
Like it? Create your own at GoAnimate.com
Interference
Interference is referred to as the collision and merging of two waves. When two waves combine, the sum of the amplitudes at different points of each wavelength produces the resulting wave. These results are known as constructive and destructive interference. Many factors are considered in the result of a particular interference. For example: Amplitude, Wavelengths, Timbre, Etc.
Constructive Interference
Constructive interference occurs when the amplitude of both waves at a particular point are either above the node. The same holds true for amplitudes below the node. Because they are both in the same direction, the "quantities" would be added and still in the same direction. This happens most consistently when two waves of the exact same frequency are played together.
Destructive Interference
Destructive interference occurs when the amplitude of one of the two waves at a particular point is above the node while the other is below the node. Because they are in opposite directions of the node, the "quantities" cancel each other out. This occurs most consistently when two waves of the exact same frequency are played together but completely out of phase.
Harmonics
Whenever a note is played on any instrument, it sends out multiple simultaneous frequencies. The original desired note that was played by the instrument is called the fundamental frequency, and the other tones that formed as a result of it are called modes. The frequencies of the higher modes are called overtones, which are apparent in all instruments; however, it differs between percussive and wind instruments. Wind instruments produce overtones called harmonics, which are named so because the overtones are "harmonically" related to the fundamental frequency that was produced by the instrument. Harmonics are simply multiples of the fundamental frequency that occur simultaneously (100 Hz, 200 Hz, 300 Hz, etc.). If each overtone is related to one another harmonically, then each one, including the fundamental frequency, can be classified as a harmonic. The fundamental frequency is essentially the first harmonic, and then first overtone becomes the second harmonic, which means the second overtone is the third harmonic, etc. Every instrument has its own unique spectrum of sound that outputs different harmonics whenever a tone is played; hence the explanation for timbre.
Hornbostel-Sachs System
Instruments are normally classified by their cultural background, how they produce sound (as well as the sound they produce), acoustics, and many other characteristics. This method of organization is appropriately called organology. A common method of classifying an instrument is the type of element that is associated with it, which can be traced back to Roman and Greek times. The five types elements that instruments are classified under are as follows: solids (gaiaphones), liquids (hydraulophones), gases (aerophones), plasma (plasmaphones), and quintessential (electrophones). [2] One well known classification system is the Hornbostel-Sachs system. It was put together by ethnomusicologist Erich Moritz von Hornbostel and musicologist Curt Sachs. The model is based off of the Dewey Decimal classification system and categorizes instruments based on their shape, air columns, the strings, and the membrane.[3]
I: Idiophones
This level includes any instrument that emits sound directly from its body after being struck without the assistance of an air column, membrane or string. They are classified into different sub-genres based on the method that they are stricken. Idiophones are also known as "gaiaphones" because they are solid instruments that maintain their shape.
Examples of idiophones include:
II: Membranophones
This level includes any instrument that produces sound from the vibration of its membrane. Nearly all drums can be placed into this category because their heads vibrate whenever struck by an object. These instruments can also be classified as gaiaphones.
Examples of membranophones include:
III: Chordophones
Instruments classified in this system create sound from the vibration of its string(s). The pitch of the instrument is primarily based on the tension in the string or primarily rely on a resonator box etc. Like idiophones and membranophones, these would also be gaiaphones.
Examples of chordophones include:
IV: Aerophones
This level includes the instruments where the production of sound is simply made from air. There are many sub levels in this category because there are many kinds of wind instruments with different structures and embouchures required to play them. Some do not require keeping air inside of the instrument itself to produce sound while most require a body in which to resonate. This level maintains the name of the element from which it originates.
Examples of aerophones include:
V: Electrophones
The fifth category includes instruments that create sound from electrical means. This category is more broadly known as the quintessential element because it also involves processes not limited by matter.
Examples of electrophones include:
Experiment
We conducted an experiment to determine how the change in timbre of a wave would affect the resultant tones of the two played notes. The experiment consisted of recording multiple tones on four different instruments. The procedure, results, etc. have been outlined below.
Materials
Procedure
Planned Procedure
1. Start up the TrueRTA Software and bring up the Oscilloscope Mode. This will take the imported sound files and convert them to a graph in real time.2. Plug in the microphone and change the software input to that microphone.
3. Use the software's generator function in order to produce a sine wave for a concert Bb and D to use as a reference.[4] Save each to the software memory and print.
4. Record each of these notes on all four instuments demonstrating the shape of each intstruments timbres. Save each to the software memory and print.
5. Have the Trumpet player play a third space C in the Treble Clef and the Clarinet player play a fourth space E in the Treble Clef at a comfortable Forte while recording. The resultant tone should be a fourth space G in the Bass Clef in accordance to the frequencies. Save the graphs to memory and print.
6. Change to the software's frequency analyzer. Repeat the same pitches. This should should show evidence of lower frequency waves due to the resultant tone. Save and Print these bar graphs.
7. Repeat steps 5 and 6 with the following pitches: Trumpet-C and Tenor Sax-E, French Horn-F and Clarinet-E, and French Horn-F and Tenor Sax-E. All resultant tones should be a low G in accordance to the frequencies.
Actual Procedure Differences
1. We recorded all individual pitches with the use of a metronome, as opposed to using the generator function to produce "control" graphs, with only the frequency analyzer and saved each to memory.2. We repeated this process for the combinations of all instruments, again with only the frequency analyzer, and saved each to memory.
Problems
1. We found it much to difficult to get an accurate enough graph of each example of timbre through the oscilloscope mode.2. We were unable to figure out how to change the setting on the frequency analyzer to give us a more accurate reading, but the data obtained show sufficient results.
Data
(Hz)
Horn Volume
(dB)
Results and Conclusions
As it turns out, the saxophone is a very interesting instrument. For this experiment, we used a tenor saxophone which, to the ear, actually sounds an octave and one whole step lower than its written note. When we recoded and graphed the frequency levels, we saw that it had picked up the low frequencies the strongest as expected. However, we noticed an odd data sample. It actually produced a high frequency sound wave as well! At first, I figured that it was due to some sort of outside interference. We recorded the tenor saxophone three separate times, and all three times we got similar results. When we recorded the Clarinet, Trumpet and French Horn, there was no evidence of these high pitch frequencies outside of the expected frequencies. For each combination of these instruments, we saw great increases in the 100-200Hz region. The most significant of these increases was in the Clarinet/Trumpet combination which was to be expected as these two are our main instrument and likely to show the optimal results.
References
The Physics of Sound
Elemental Organology
Frequency of Musical Notes